The proposed clinical research is concerned with the application and evaluation of biofeedback and relaxation methods in the regulation of blood pressure in patients with essential hypertension. Patients with mild (to moderate or severe) hypertension will be studied intensively and assigned to drug treatment, biofeedback, a simple relaxation procedure, or a simple "self-help placebo" condition in which patients monitor their own pressure and all laboratory measurements are taken as in the other treatments. Extensive baseline data, including home blood pressure recordings by the patients, medical status, hormonal and hemodynamic measurements, personality tests, and psychophysiological reactivity testing, will be obtained. Following each treatment, the same measures will be repeated for purposes of evaluation, and the patients will then be followed for a minimum of three months to determine the degree to which reductions in pressure persist. In some cases, patients will then be assigned to a second treatment in order to gain additional information about the differential effectiveness of the treatments. The broad objective of this research is to evaluate the usefulness of behavioral approaches to hypertension, as a possible adjunctive method of treatment, or as a possible alternative to drug treatment for patients whose hypertension is not adequately controlled with medication, or for patients having undesired side effects of medication. A behavioral therapy may permit reduction of the required dosage of medication and of accompanying side effects. The proposed intensive case studies will provide systematic evidence concerning the value and potential of behavioral methods such as biofeedback and relaxation, if the answer is positive, at a later stage large-scale comparative studies of different behavioral strategies of treatment will be proposed, and applications of the procedures to other varieties of hypertensive disorder will be examined.